CN110735432A - Method for clearing pile foundation and controlling parameters in shield tunneling machine over-invasion limit tunnel range - Google Patents

Method for clearing pile foundation and controlling parameters in shield tunneling machine over-invasion limit tunnel range Download PDF

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CN110735432A
CN110735432A CN201911127902.0A CN201911127902A CN110735432A CN 110735432 A CN110735432 A CN 110735432A CN 201911127902 A CN201911127902 A CN 201911127902A CN 110735432 A CN110735432 A CN 110735432A
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pile
invasion
limit
piles
inclinometer
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李应姣
张桥
杨燕青
阳紫东
彭刚
王策
刘晓杰
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China Railway 11th Bureau Group Urban Rail Engineering Co Ltd
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China Railway 11th Bureau Group Urban Rail Engineering Co Ltd
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    • EFIXED CONSTRUCTIONS
    • E02HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02DFOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
    • E02D9/00Removing sheet piles bulkheads, piles, mould-pipes or other moulds or parts thereof
    • EFIXED CONSTRUCTIONS
    • E21EARTH OR ROCK DRILLING; MINING
    • E21DSHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
    • E21D11/00Lining tunnels, galleries or other underground cavities, e.g. large underground chambers; Linings therefor; Making such linings in situ, e.g. by assembling
    • E21D11/04Lining with building materials
    • E21D11/10Lining with building materials with concrete cast in situ; Shuttering also lost shutterings, e.g. made of blocks, of metal plates or other equipment adapted therefor
    • E21D11/105Transport or application of concrete specially adapted for the lining of tunnels or galleries ; Backfilling the space between main building element and the surrounding rock, e.g. with concrete
    • EFIXED CONSTRUCTIONS
    • E21EARTH OR ROCK DRILLING; MINING
    • E21DSHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
    • E21D9/00Tunnels or galleries, with or without linings; Methods or apparatus for making thereof; Layout of tunnels or galleries
    • E21D9/06Making by using a driving shield, i.e. advanced by pushing means bearing against the already placed lining
    • E21D9/08Making by using a driving shield, i.e. advanced by pushing means bearing against the already placed lining with additional boring or cutting means other than the conventional cutting edge of the shield

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Abstract

The invention provides a clearing and parameter control method for pile foundations in shield over-limit-invasion tunnel ranges, which comprises the following steps of embedding an inclinometer in a central guide hole of an invasion limit pile, constructing plain concrete blocking piles around the invasion limit pile, constructing the blocking piles to the height of the invasion limit pile 1/3-1/2, backfilling soil, constructing a jet grouting pile in the area above the blocking piles, installing a protective sleeve on the ground of the top of the invasion limit pile, clearing the invasion limit pile by using a pile flushing method, backfilling concrete in a flushing hole to form a replacement pile after a pile body is cleared, adjusting and controlling specific tunneling parameters in a targeted manner when the shield tunnels through the plain piles, and simultaneously adopting WSS to track grouting according to the ground surface settlement monitoring condition to fill underground subsidence soil in time to ensure the ground stability.

Description

Method for clearing pile foundation and controlling parameters in shield tunneling machine over-invasion limit tunnel range
Technical Field
The invention aims at the field of urban rail construction, and particularly relates to a method for clearing pile foundations and controlling parameters in the range of shield over-limit tunnels.
Background
With the continuous development of national economy and urban traffic construction in China, the climax of underground rail transit construction has been raised in China, underground reinforced concrete pile foundations cannot be avoided completely in the planning and construction range of subways, and the penetration of the reinforced concrete pile foundations into the tunnel range is often caused due to shallow underground tunnel burial depth. The subway tunnel is constructed by adopting a shield method, if a shield directly cuts a limit pile foundation, a pile foundation steel bar is easily wound around a shield machine cutter head to continuously detour the soil around the shield machine cutter head and even lock the shield machine cutter head. In order to ensure the smooth construction of the shield, the invasion limiting pile foundation body needs to be removed.
Compared with the pile pulling method and the blasting method, the pile punching method is methods which are low in cost and efficient in construction, and particularly adopts a punching pile driver to directly punch and remove the pile foundation in the limited tunnel range.
Disclosure of Invention
In order to solve the technical problems, the methods for clearing pile foundations in the shield over-limit tunnel range and controlling parameters can quickly and efficiently solve the pile foundations intruding into the tunnel range, and reduce the risk that a cutter head is wound and tied by steel bars in the shield construction process.
In order to ensure the removal of pile foundations in the shield tunnel range, the invention provides an method for removing pile foundations in the shield over-limit tunnel range, which is characterized by comprising the following steps:
(1) determining the position of an intrusion limit pile in the shield tunnel range, then leading a hole through a drilling machine at the center of each intrusion limit pile and embedding an inclinometer, wherein the drilling depth of the inclinometer is up to the position below the pile bottom of the intrusion limit pile, and the top of the inclinometer is higher than the pile top of the intrusion limit pile; determining the integrity of a pile body of the limit-invading pile by drilling and coring, determining the length and the gradient of the limit-invading pile by an inclinometer after an inclinometer is buried, and setting a construction pile flushing plane range according to the determined length and gradient of the pile;
(2) constructing plain concrete clamping piles in four directions of the invasion limiting pile according to the positioning position of the invasion limiting pile, wherein the outer edge of each clamping pile in each direction is 10-20cm away from the side of the invasion limiting pile; firstly, determining the position of a blocking pile, constructing a pile hole to a position below the pile bottom of an invasion limiting pile by adopting a rotary drilling rig, pouring underwater concrete to a height of 1/3-1/2 of the invasion limiting pile to form the blocking pile, and then backfilling soil into the pile hole to the pile top of the invasion limiting pile;
(3) after the construction of the blocking piles in the step (2) is finished, constructing 3-5 circles of occluded jet grouting piles outside the invasion limiting piles by taking the centers of the invasion limiting piles as the circle centers to form a rotating pile reinforcing body, wherein the pile bottoms of the jet grouting piles extend to the pile tops of the blocking piles in the step (2), and bodies are connected among the jet grouting piles in contact with the blocking piles;
(4) after the construction of the reinforcing body of the rotary pile in the step (3) is completed, installing a protective sleeve at a position corresponding to the penetration limiting pile on the ground, wherein the protective sleeve is fixed on the ground, the height of the protective sleeve is 0.8-1.2 m, the inner diameter of the protective sleeve is 20-50 cm larger than that of a percussion drill bit, and an inner through hole is opposite to the penetration limiting pile;
(5) after the protective sleeve in the step (4) is installed, taking out the inclinometer pipe, pouring bentonite slurry and clay required by pile punching into the protective sleeve, suspending an impact drill bit by using an impact type pile driver to aim at the central position of the protective sleeve for reciprocating impact, crushing a pile body of the limit-invading pile into crushed slag, and taking the crushed slag out of the ground through slurry circulation; simultaneously, in the impact process, breaking the steel bars in the pile body of the intrusion limiting pile, and sucking out the broken steel bars by using a strong magnet or directly using an impact drill to exit the area below the elevation of the tunnel bottom; the diameter of the percussion drill bit is 10 cm-20 cm larger than the pile diameter of the invasion limiting pile; the cleaned steel bars are weighed in time, so that no large amount of steel bars are left in the tunnel range;
(6) after the limit pile that invades in step (5) is washed out and is accomplished, the concrete under water fills, forms plain concrete replacement pile in the position of invading the limit pile, the position that replaces 2 ~ 5m above the pile head elevation of stake exceeds the tunnel top surface to backfill clay to invading the original elevation of limit pile in the residual hole position, guarantee to punch a hole and backfill closely knit, avoid appearing collapsing even roof fall phenomenon among the tunnelling process.
The invention has the technical scheme that: after the construction of the clamping pile in the step (2) and the construction of the jet grouting pile in the step (3) are completed, a probe of an inclinometer is placed in the invasion limiting pile through an inclinometer tube to monitor the inclination condition of a pile body, whether the invasion limiting pile is damaged by the construction of the plain concrete clamping pile and the jet grouting pile is determined, if the damage and the inclination occur, the construction needs to be stopped, and the construction scheme is determined again.
The method has the technical scheme that in the step (1), a geological drilling machine is used for guiding holes, the diameter of a drilled hole is 75-110 mm, the depth of the drilled hole is 2-5 m to the bottom of the invasion limiting pile, a plastic inclinometer with the diameter of 35-60 mm is adopted as the inclinometer, the top of the inclinometer is 0.2-0.3 m higher than the top of the invasion limiting pile, the length and integrity of the invasion limiting pile can be rechecked on the aspect of the inclinometer , and in addition, whether the invasion limiting pile is damaged by construction of a clamped plain concrete pile and a jet grouting pile before the invasion limiting pile is flushed on the aspect of , and the condition of the pile foundation of the invasion limiting pile is mastered in time.
The invention has the technical scheme that: plain concrete screens stake in step (2) is equipped with four, and four screens stakes become 90 degrees contained angles and distribute and encroaching limit stake all around, and the stake end elevation is lower 2.5 ~ 3.5m than encroaching limit stake, and four screens stakes all adopt C20 underwater concrete to pour and form, and every screens stake is poured to the 1/3 high department of encroaching limit stake, can reduce cost, and the diameter of its screens stake is 550 ~ 650 mm.
The invention has the technical scheme that: in the step (3), the diameter of the jet grouting pile is 550-650 mm, the jet grouting pile is occluded by 100-200 mm, the bottom of the jet grouting pile is connected with the blocking pile, and specifically, when a drill rod of the jet grouting pile drills to the pile top of the blocking pile, in-situ rotary guniting is carried out for 1-3 min, so that the jet grouting pile is connected with the blocking pile; the short-section steel bars for preventing the broken invasion limiting pile are clamped into the surrounding soil and still in the range of the tunnel.
The invention has the technical scheme that: the protective sleeve in the step (4) is formed by welding an upper cylinder and a lower annular fixing seat, a plurality of triangular rib plates are welded between the cylinder and the annular fixing seat, a plurality of anchoring holes are formed in the annular fixing seat, the upper cylinder is made of an annular steel plate with the thickness of 2-3 cm, and the annular fixing base is used for fixing and smashing the ground through 6-8 rivets. The protective sleeve is fixed subaerial with long riveting bolt, provides space deposit and dashes required bentonite mud and a small amount of clay of stake, can prevent to dash the garrulous sediment of concrete of pounding and splash and hinder the people, and simultaneously, the protective sleeve still plays the effect of fixed impact hammer, guarantees to dash the stake machine impact hammer and smashes when invading the limit stake, can not incline the off tracking.
The invention has the technical scheme that: and (5) crushing the pile body of the penetration limiting pile into crushed slag and taking the crushed slag out of the ground through mud circulation, namely, pumping the mud by using a mud pump while impacting, so that the mud is ejected from the bottom end of the drill bit and mixed with the crushed slag of the pile body, continuously overflowing from the bottom of the hole to the orifice in a positive circulation mode, and taking the crushed slag out of the ground.
The parameter control method for the shield tunneling machine intrusion tunnel range is characterized by comprising the following specific steps of clearing pile foundations in the shield tunneling machine intrusion tunnel range according to the method, controlling the shield tunneling speed to be 10-15mm/min, controlling the torque 2700 + 3000knm, controlling the rotating speed of a cutter head to be 1.5r/min, controlling the thrust 4500 + 5000t, and controlling the soil bin pressure to be 0.1-0.3 bar greater than the soil pressure at the top of the cutter head when the shield tunneling machine passes through the intrusion tunnel range, and adopting WSS to track grouting and fill underground subsidence soil bodies in time according to the ground subsidence monitoring condition.
The invention has the technical scheme that: performing WSS tracking grouting in an area with the ground surface settlement exceeding 10mm, wherein the drilling depth is 5m above a shield machine, the grouting adopts double-liquid slurry consisting of water glass and cement slurry, the grouting depth is more than 2-3 m of a cutter head, the water-cement ratio of the cement slurry is 1:1, the initial setting time of the double-liquid slurry is controlled at 30-40s, and the final hole pressure of the grouting is controlled at 1 Mpa; the stratum around the replacement pile is reinforced by tracking grouting, and a grouting curtain is formed at the edge of the pile foundation, so that the pressure of a soil bin is normal in the tunneling process of the shield tunneling machine, and the pressure relief condition is prevented.
The invention has the beneficial effects that:
(1) before pile foundation clearing is carried out, the length and the integrity of the invasion limiting pile can be detected before construction by embedding the positioning detection pipe in the center drilling hole of the invasion limiting pile, whether the invasion limiting pile is damaged by construction of the clamping element concrete pile and the jet grouting pile or not is detected before the invasion limiting pile is flushed, the condition of the invasion limiting pile can be accurately mastered in advance, and a basis is provided for subsequent flushing and removing work of the invasion limiting pile.
(2) According to the construction method, four plain concrete blocking piles are constructed at the bottom of the intrusion limiting pile, so that the problem that the pile foundation is displaced when a small section of pile foundation is remained in the process of removing the intrusion limiting pile is effectively solved, the intrusion limiting pile can be completely flushed out of the range of a tunnel, the blocking piles are poured to the position of 1/3 th of the intrusion limiting pile, the cost is reduced, and then the rest part is backfilled with original soil;
(3) according to the invention, the invasion limiting pile is used as the center, the occluded jet grouting pile is constructed on the periphery of the invasion limiting pile, the soil body around the invasion limiting pile is reinforced, the adverse effect on the disturbance of the peripheral stratum in the construction process is reduced, and the problem of ground surface hole collapse when the pile flushing machine flushes the invasion limiting pile is solved; and moreover, because the rotary spraying pile stratum is formed around the invasion limiting pile, the soil body strength is increased, and the possibility that the reinforcing steel bars are retained in the peripheral soil body in the pile punching process is avoided.
(4) The invention combines the practical situation, replaces the steel casing in the original pile-punching with the special sleeve seat on the ground, provides the space for storing mud in aspects, ensures the verticality of the impact drill in the pile-punching process, reduces the construction cost, saves the time for embedding the steel casing, and greatly improves the construction efficiency.
(5) In the invention, WSS tracking grouting is carried out in time in the shield tunneling process, gaps around a pile foundation and surrounding soft strata are filled, irregular settlement of the ground is prevented after a shield tunneling machine penetrates through a plain concrete pile and enters the soft strata for tunneling, and the safety of ground buildings in the tunneling process is ensured.
Drawings
FIG. 1 is a schematic view of a construction structure according to an embodiment of the present invention;
FIG. 2 is a cross-sectional view taken along line A-A of FIG. 1;
FIG. 3 is a cross-sectional view taken along line B-B of FIG. 1;
fig. 4 is a schematic view of the structure of the protective sleeve of the present invention.
In the figure: the method comprises the following steps of 1-invasion limiting pile, 2-inclinometer pipe, 3-protective sleeve, 3-1-cylinder, 3-2-annular fixed seat, 3-triangular rib plate, 4-clamping pile, 5-jet grouting pile and 6-tunnel.
Detailed Description
The invention is further illustrated with reference to the following examples.
The embodiment aims at a certain shield interval of State subways, the interval is constructed by a shield method, the left line length of the interval is 1098.87m, the right line length of the interval is 1099.188m, the soil covering and burying depth of an arch crown of an interval tunnel is about 7.5-13.8 m, the line burying depth is about 13.5-19.8 m, 35 original house reinforced concrete pile foundations are arranged on a descending line pushing line in the interval, the pile foundations invade a shield tunnel top plate for about 3m, the pile foundations invade the shield descending line, the distance from the center of the descending line of the tunnel is not equal to 0-3 m, the length of each pile is limited by invasion and 12m, and the diameter of a pile body is 12m
Figure BDA0002277430960000062
The length of the reinforcement cage is 11.8m, the main reinforcement adopts phi 20 screw-thread steel and stirrupRound steel, poured under water C30 concrete. The underground water level of the section is mostly in pore diving, and the static water level burial depth is 1 m-2.9 m. The geological conditions of the pile foundation group region are sequentially as follows from top to bottom:<1-1>、<1-2>the artificial soil-filling layer is filled in the soil,<4-2A>、<4-2B>、<4N-2>alluvial soil layer (local inclusions)<3-2>Medium coarse sand layer) followed by<3-2>、<3-3>A sand layer and<9C-2>slightly weathered rock formations. The house pile foundation is mainly located in a soil filling layer, a silty clay layer and a sand layer. Tunnels mainly traverse sand and slightly weathered rock formations. The interval adoptsAnd (3) constructing by a shield method, wherein a cutter head and a cutter which are adapted to shield tunneling and are prepared can not cut the reinforced concrete invasion limiting pile.
Aiming at the construction project, the construction method for removing the pile foundation in the shield tunnel range is adopted for construction, and the construction method specifically comprises the following steps:
(1) burying an inclinometer 2: firstly, the position of an invasion limiting pile 1 is detected, a geological drilling machine is used for leading a hole in the center of each invasion limiting pile 1, the diameter of the drilled hole is 90mm, then a plastic inclinometer pipe 2 with the diameter of 70mm is embedded, the inclinometer pipe 2 needs to extend out 2m below the pile bottom, the embedded inclinometer pipe 2 needs to leak out 0.2m of the pile head, and in the embedding process, the sealing integrity of the joint of the inclinometer pipe needs to be ensured, and meanwhile, the verticality of the inclinometer pipe also needs to be ensured. And (3) putting a probe of the inclinometer into the inclinometer through the inclinometer pipe to detect the invasion limiting pile body, and finding that the pile length is 11m-13m, and the pile body of the invasion limiting pile is complete except for cracks in the middle parts of the No. 3 pile and the No. 12 pile.
(2) Constructing a lower plain concrete clamping pile 4: because the majority of the pile body of the invasion limiting pile 1 is positioned in the silty clay layer and the sand layer, in order to prevent the invasion limiting pile from shifting in the pile washing process, 4 plain concrete cast-in-place piles with the diameter of 600mm are constructed in four different directions of each invasion limiting pile 1 and are poured by C20 underwater concrete. The outer edge of the clamping pile is 10-20cm away from the edge of the invasion limiting pile, the elevation of the pile bottom is 3m lower than that of the invasion limiting pile, the pile is poured to the position of 1/3 height of the invasion limiting pile, the upper part of a drilled hole of the clamping pile is backfilled to the ground height, as shown in fig. 3, the four clamping piles are distributed in four directions of the periphery of the invasion limiting pile, and a 90-degree included angle is formed in the center of the invasion limiting pile.
(3) And constructing a middle upper soil body reinforcing jet grouting pile. Because the stratum of the pile body of the invasion limiting pile 1 is soft, the reinforcing steel bars are reserved in the range of the tunnel in order to prevent the invasion limiting pile from being washed out. The research of the project department determines that the invasion limiting piles are used as centers, as shown in fig. 2, 3 circles of mutually-meshed rotary spraying piles 5 are constructed on the periphery of each invasion limiting pile, the diameters of the adjacent rotary spraying piles 5 are 600mm, the meshes are 150mm, the pile center distance is 450mm, the rotary spraying piles 5 are connected with the clamping positions 4, and the pile top elevation is the ground elevation. The reinforcing of the jet grouting pile adopts P.O 42.5.5R Portland early strength cement, and the water cement ratio of the slurry is 1-1.5; in the construction process, the pressure is controlled to be 22-25 MPa, the slurry flow is 40-70L/min, the rotary spraying lifting speed is preferably controlled to be 5-25 cm/min, the rotating speed is preferably controlled to be 10-20 r/min, and when a drill rod drills to the pile top of the blocking pile, the rotary spraying is performed in situ for 1-3 min, so that the connection between the rotary spraying pile and the blocking pile is ensured. After the construction of the jet grouting pile is completed, the limiting pile body is detected again through the positioning monitoring pipe, and the influence on the limiting pile body is found when the clamping pile construction and the jet grouting pile construction are carried out.
(4) And installing a ground protective sleeve 3. A protective tower cylinder is made of an annular steel plate with the thickness of 2cm in advance, the structure of the protective sleeve is shown in figure 4, the protective sleeve 3 is composed of an upper cylinder 3-1 and a lower annular fixed seat 3-2, and a plurality of triangular rib plates 3-3 are welded between the cylinder 3-1 and the annular fixed seat 3-2; the diameter of the cylinder 3-1 is 1.4m, the height is 1.2m, annular wing plates are erected at the upper end and the lower end, the width of the upper annular wing plate is 5cm, and the width of the lower annular wing plate is 50cm to form an annular fixed seat 3-2, so that the contact area between the sleeve seat and the ground is increased. 6-8 circular holes are reserved on the annular fixed seat 3-2, and rivets penetrate through the circular holes before the pile punching is carried out, so that the circular fixed seat is fixed on the ground; the sleeve body of the sleeve seat is provided with annular and vertical ribbed plates with the width of 1cm, and the distance between the ribbed plates is 20 cm.
(5) And (3) construction of a flushing and removing invasion limiting pile: this project is washed out to invading the limit stake with impact type stake machine, and the percussion drill bit diameter is 1 m. After the protective sleeve in the step (4) is installed, taking out the inclinometer pipe, and after the pile machine is in place, adding the prepared bentonite slurry and a small amount of clay into the protective tower barrel 3 installed in the step (4), wherein the bentonite slurry and clay colloid rate is 95% and the sand content is less than 4%; then starting an impact type pile foundation suspension impact drill bit to aim at the central position of the protective sleeve for reciprocating impact, crushing the penetration limiting pile body into crushed slag, breaking the steel bars in the penetration limiting pile body, and sucking out the crushed slag by using a strong magnet or directly using the impact drill bit to exit the area below the elevation of the tunnel bottom; and simultaneously, mud is pumped by a mud pump, so that the mud is ejected from the bottom end of the drill bit and is mixed with the crushed slag of the pile body, and the mud continuously overflows from the bottom of the hole to the orifice in a positive circulation mode, so that the crushed slag is taken out of the ground. The footage needs to be properly controlled in the impacting process, and the drilling is carried out at the bottom of the sleeve seat at a low speed, so that a good wall protection effect is ensured at the bottom; and drilling to 1m below the bottom of the pile casing at normal speed according to actual conditions. When the steel bar is sucked out by the magnet, the steel bar is firstly adsorbed along the periphery of the hole wall and then the steel bar in the hole is adsorbed until the adsorption for 3 times is all scrap iron and no steel bar exists. And (4) stacking the adsorbed reinforcing steel bars separately, weighing the mass of the reinforcing steel bars by using a platform scale after the reinforcing steel bars are dried in the sun, and recording the weight of the reinforcing steel bars to ensure that all the reinforcing steel bars are adsorbed.
(6) And pouring the replacement plain concrete pile. And after the pile punching machine finishes pile punching, cleaning holes by a pulp changing method. And after hole cleaning is finished, concrete is poured, the replacement pile is poured from the bottom of a hole groove formed by punching the pile, and the pouring is carried out until the position of the replacement pile is 5m above the tunnel. The replacement pile is cast by a guide pipe method, the pipe diameter of the guide pipe is 250mm, the cast concrete is C20 underwater concrete, the concrete has good workability, broken stone grading is 5-25 mm, medium coarse sand is selected, a water reducing agent is doped, the slump constant is controlled to be 18-22 cm, and the water-cement ratio is not more than 0.6. The first concrete pouring is not less than 2m3 (standard groove section), so that the first pouring concrete can bury the guide pipe, the pouring process needs to be continuously carried out, the interruption time is not more than 30 minutes, and the integrity of the pile body of the replacement pile is ensured.
(7) After all invasion limit pile foundations in a shield area are removed, a shield tunneling process can be carried out, large blocks are easily generated in the tunneling process due to low strength of plain piles, therefore, in the tunneling process, tunneling parameters are required to be controlled, the speed is controlled to be 10-15mm/min, the torque is 2700 + 3000knm, the rotating speed of a cutter head is 1.5r/min, the thrust is 4500 + 5000t, soil output and pressure of a soil bin are strictly monitored, the pressure of the shield soil bin, the soil output condition of a soil outlet and ground settlement are required to be monitored, the pressure of the soil bin is is 0.2bar greater than the soil pressure of the top of the cutter head, when the shield tunneling machine reaches 18 piles, the ground settlement of the cutter head and a tail of the shield machine is monitored to be 12mm, in order to ensure the safety of a ground building, an emergency shutdown measures are taken at the top of the shield, WSS tracking grouting is carried out at the corresponding position of the shield tail and the cutter head of the shield machine, the drilling depth is 5m above the shield machine, double-grouting water glass and the double-grouting cement slurry is used for grouting, the initial water glass and the grouting is used for grouting, the cement slurry is controlled at the time of the initial water glass and the pressure of the normal grouting is 1: 1mpa, the slurry is controlled, and the slurry is used for controlling the grouting of the slurry.
After the construction method for clearing the pile foundation in the shield tunnel range is adopted in the construction project, the shield can be helped to smoothly pass through the penetration limiting pile, the quality of the formed tunnel is ensured, and powerful guarantee is provided for tunnel penetration.
It should be noted that those skilled in the art can make various changes and modifications without departing from the spirit of the invention, and therefore the scope of the invention should be determined by the appended claims.

Claims (9)

1, kinds of shield constructs and crosses and invades the interior pile foundation clearance method of limit tunnel range, characterized by comprising the following steps specifically:
(1) determining the position of an intrusion limit pile in the shield tunnel range, then leading a hole through a drilling machine at the center of each intrusion limit pile and embedding an inclinometer, wherein the drilling depth of the inclinometer is up to the position below the pile bottom of the intrusion limit pile, and the top of the inclinometer is higher than the pile top of the intrusion limit pile; determining the integrity of a pile body of the limit-invading pile by drilling and coring, determining the length and the gradient of the limit-invading pile by an inclinometer after an inclinometer is buried, and setting the range of a flushing plane of the pile according to the determined length and gradient of the pile;
(2) constructing plain concrete clamping piles in four directions of the invasion limiting pile according to the positioning position of the invasion limiting pile, wherein the outer edge of each clamping pile in each direction is 10-20cm away from the side of the invasion limiting pile; firstly, determining the position of a blocking pile, constructing a pile hole to a position below the pile bottom of an invasion limiting pile by adopting a rotary drilling rig, pouring underwater concrete to a height of 1/3-1/2 of the invasion limiting pile to form the blocking pile, and then backfilling soil into the pile hole to the pile top of the invasion limiting pile;
(3) after the construction of the blocking piles in the step (2) is finished, constructing 3-5 circles of occluded jet grouting piles outside the invasion limiting piles by taking the centers of the invasion limiting piles as the circle centers to form a rotating pile reinforcing body, wherein the pile bottoms of the jet grouting piles extend to the pile tops of the blocking piles in the step (2), and bodies are connected among the jet grouting piles in contact with the blocking piles;
(4) after the construction of the reinforcing body of the rotary pile in the step (3) is completed, installing a protective sleeve at a position corresponding to the penetration limiting pile on the ground, wherein the protective sleeve is fixed on the ground, the height of the protective sleeve is 0.8-1.2 m, the inner diameter of the protective sleeve is 20-50 cm larger than that of a percussion drill bit, and an inner through hole is opposite to the penetration limiting pile;
(5) after the protective sleeve in the step (4) is installed, taking out the inclinometer pipe, pouring bentonite slurry and clay required by pile punching into the protective sleeve, suspending an impact drill bit by using an impact type pile driver to aim at the central position of the protective sleeve for reciprocating impact, crushing a pile body of the limit-invading pile into crushed slag, and taking the crushed slag out of the ground through slurry circulation; simultaneously, in the impact process, breaking the steel bars in the pile body of the intrusion limiting pile, and sucking out the broken steel bars by using a strong magnet or directly using an impact drill to exit the area below the elevation of the tunnel bottom; the diameter of the percussion drill bit is 10 cm-20 cm larger than the pile diameter of the invasion limiting pile;
(6) and (5) pouring underwater concrete after the limit pile is flushed in the step (5), forming a plain concrete replacement pile at the position of the limit pile, wherein the pile top elevation of the replacement pile is higher than the position 2-5 m above the top surface of the tunnel, and backfilling clay at the position of the residual hole until the original elevation of the limit pile is invaded.
2. The method for removing pile foundation in the shield over-invasion-limit tunnel according to claim 1, wherein after the construction of the retaining pile in step (2) and the construction of the jet grouting pile in step (3) are completed, a probe of an inclinometer is placed in the invasion-limit pile through an inclinometer tube to monitor the inclination condition of the pile body, determine whether the construction of the plain concrete retaining pile and the jet grouting pile damages the invasion-limit pile, if so, the construction is stopped, and the construction scheme is adjusted.
3. The method for removing pile foundation in the shield tunneling range beyond the limit of invasion according to claim 1, wherein a geological drilling machine is used for guiding holes in step (1), the diameter of the drilled holes is 75-110 mm, the depth of the drilled holes is 2-5 m from the bottom of the limit-invasion pile, the inclinometer is a plastic inclinometer with the diameter of 35-60 mm, and the top of the inclinometer is 0.2-0.3 m higher than the top of the limit-invasion pile.
4. The pile foundation removing method in the shield tunneling range beyond the limit of invasion according to claim 1, wherein the number of the plain concrete retaining piles in step (2) is four, the four retaining piles are distributed around the limit of invasion at 90-degree included angles, the elevation of the pile bottom is 2.5-3.5 m lower than that of the limit of invasion, the four retaining piles are all cast by C20 underwater concrete, and each retaining pile is cast to the 1/3 height of the limit of invasion and has a diameter of 550-650 mm.
5. The method for removing pile foundation in the shield tunneling machine beyond the limit of invasion according to claim 1, wherein in step (3), the diameter of the jet grouting pile is 550-650 mm, the jet grouting pile is occluded 100-200 mm, the bottom of the jet grouting pile is connected with the blocking pile, specifically, when a drill rod of the jet grouting pile drills to the top of the blocking pile, the jet grouting pile is rotated in situ for 1-3 min, and the connection between the jet grouting pile and the blocking pile is ensured.
6. The method for removing pile foundation in the shield tunneling machine crossing the invasion limit tunnel according to claim 1, wherein the protective sleeve in step (4) is formed by welding an upper cylinder and a lower annular fixing seat, a plurality of triangular rib plates are welded between the cylinder and the annular fixing seat, a plurality of anchoring holes are formed in the annular fixing seat, the upper cylinder is made of an annular steel plate with the thickness of 2-3 cm, and the annular fixing seat is fixed on the ground through 6-8 rivets.
7. The method for removing pile foundation in the shield tunneling range beyond the limit of invasion according to claim 1, wherein the step (5) comprises breaking the limit pile body into fragments and taking the fragments out of the ground through mud circulation, specifically, pumping mud with a mud pump while impacting, so that mud is ejected from the bottom end of the drill bit and mixed with the fragments of the pile body, and continuously overflowing from the bottom of the hole to the hole in a positive circulation manner, and taking the fragments out of the ground.
The parameter control method for the limited tunnel penetration range of the shield tunneling machines is characterized by comprising the following specific steps of clearing pile foundations in the limited tunnel penetration range of the shield tunneling machines according to any method in claims 1 to 7, controlling the shield tunneling speed to be 10-15mm/min, controlling the torque to be 2700-3000knm, controlling the rotation speed of a cutterhead to be 1.5r/min, controlling the thrust to be 4500-.
9. The parameter control method for the shield tunneling machine to limit the penetration range of a tunnel according to claim 8, wherein WSS tracking grouting is performed in an area where the ground surface subsidence exceeds 10mm, the drilling depth is 5m above the shield tunneling machine, double-liquid slurry consisting of water glass and cement slurry is adopted for grouting, the grouting depth is more than 2-3 m above a cutter head, the water-cement ratio of the cement slurry is 1:1, the initial setting time of the double-liquid slurry is controlled within 30-40s, and the final hole pressure of the grouting is controlled within 1 MPa.
CN201911127902.0A 2019-11-18 2019-11-18 Method for clearing pile foundation and controlling parameters in shield tunneling machine over-invasion limit tunnel range Pending CN110735432A (en)

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Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN111456006A (en) * 2020-04-22 2020-07-28 中铁第五勘察设计院集团有限公司 Method for breaking existing cast-in-place pile
CN111893994A (en) * 2020-07-27 2020-11-06 中交路桥建设有限公司 Pile casing-free pore-forming method for foundation pile of aeolian dune steep slope
CN113356206A (en) * 2021-06-28 2021-09-07 中铁十六局集团地铁工程有限公司 Construction method for breaking existing pile foundation
CN114837166A (en) * 2022-05-18 2022-08-02 中铁六局集团有限公司 Construction method of pile foundation for complex terrain geology in mountainous area

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN111456006A (en) * 2020-04-22 2020-07-28 中铁第五勘察设计院集团有限公司 Method for breaking existing cast-in-place pile
CN111893994A (en) * 2020-07-27 2020-11-06 中交路桥建设有限公司 Pile casing-free pore-forming method for foundation pile of aeolian dune steep slope
CN113356206A (en) * 2021-06-28 2021-09-07 中铁十六局集团地铁工程有限公司 Construction method for breaking existing pile foundation
CN114837166A (en) * 2022-05-18 2022-08-02 中铁六局集团有限公司 Construction method of pile foundation for complex terrain geology in mountainous area

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